1. Field of the Invention
The present invention relates generally to chelators and more specifically to the chelators attached to polymers.
2. Description of the Background Art
In many liquids, such as jet fuel, the presence of even ppm concentrations of metals such as Cu significantly reduces the thermal stability and performance of the liquid. Soluble chelators are commonly used for tying up these in liquids such as fuels.
A better approach is to remove the metal from fuel or other liquids by immobilizing the chelator-metal complex to a stationary phase. This removal may be accomplished by using a chelator bound to a polymer backbone. Previously, crown ethers and cryptand chelators have been immobilized on polystyrene. This immobilization has been typically performed by solid-phase reactions between the crown ether or cryptand chelator and the activated polymer. In these reactions, however, many modifiable sites on the polymer remain unsubstituted with chelator. Therefore, the polymer bearing the immobilized chelators provides a less than optimal concentration of bound chelators. This low substitution may be attributed to the inaccessibility of some of the reaction sites and the inability of the chelator, due to its molecular size or reaction conditions, to penetrate the polymer.